1. Field of the Invention
This invention relates to a one-piece plastic closure for fastening on a container comprising a lower part with a top surface in which a pouring opening is disposed, a cap pivotably connected thereto by a hinge shaft, and a security element connected in one piece to the closure.
2. Description of Prior Art
Plastic closures of the type mentioned above are known in many embodiments. See, for example, U.S. Pat. No. 3,441,161 and 4,487,324. As a rule, plastic closures with a lower part and a cap pivotably connected thereto by a hinge shaft always employ security bands which must be removed prior to the initial opening movement. The '161 patent discloses a bottle closure wherein the bottleneck itself constitutes the pouring opening and wherein the lower part thus only comprises an annular wall with a clamping bead which is connected in one piece to the tang-like upper part, a top surface being omitted. Only by the removal of the security band are the upper part and the lower part separated from each other with the exception of a remaining part used as a hinge shaft. Although such a closure can be manufactured without problems, it must be molded in the closed position, which makes the formation of the lower part with a top surface and a pouring opening disposed therein impossible. The '324 patent teaches a one-piece closure having a lower part with a top surface in which a pouring opening is disposed, a cap pivotably connected to the lower part by a hinge shaft and a security element connected in one-piece to the closure. A closure of this type is molded in the open position. In this case, the security element also is a security band disposed on the lower part which has recesses distributed over its circumference which, in the security position, are engaged by protrusions in the cap.
A similar plastic closure is also taught by U.S. Pat. No. 4,696,408. Here, too, it is first necessary to tear off a security band before the closure can be opened. In contrast to the solution in accordance with the '324 patent, this security band does not operate primarily by a positive fit which makes the initial opening impossible prior to the removal of the security band, but rather the security band makes it impossible to grip the cap as long as the security band is still disposed on the closure.
In contrast to screw closures having a security ring at one end which is connected to an annular wall of the screw cap by predetermined break points and which engage the back of an annular bead on the bottleneck, it is necessary in connection with all known plastic closures having a lower part with a top surface in which a pouring opening is disposed and having a cap pivotably connected thereto by a hinge shaft to perform an additional manipulative step prior to the initial opening movement.
Manufacture of a one-piece plastic closure as described above, having a security band, is extremely problematical. For one thing, the security bands often tear when being removed from the injection mold because they get caught in the cavities of the injection mold. In addition, the long and thin security bands have a tendency to deform, as a result of which initial closing is either made impossible or the security band tears at some of the predetermined break points during initial closing. Also, plastic closures with a security band are not esthetically pleasing. Although guaranteed secure closures are being demanded by the cosmetics industry, the known guaranteed secure closures with a security band have not been successful.
It has also been shown that many users still do not understand the function of security bands and try unsuccessfully to open the closure without removing the security band. For this reason, such closures are still wrongly torn off or unscrewed.